Scott, Jay R.; Leslie, Ward J.; Pacific Missile Test Center (International Foundation for Telemetering, 1981-10)
      This paper provides an overview of the capabilities of the ranges operated by the Pacific Missile Test Center under the management of the United States Navy. Locations, types of instrumentation, operation, and current developments are briefly discussed.

      Busby , Lawrence A.; Kramb, Edwin A. (International Foundation for Telemetering, 1981-10)
      Flight Termination Sub-Systems for range safety purposes are a part of all spacecraft launch vehicles. The Command Receiver and Decoder portion of this sub-system receives the rf up-link signal and initiates the flight termination action. For launch vehicles for unmanned spacecraft, the range safety up-link command signal is composed of selected IRIG audio tones, in a specified sequence, frequency modulated on an rf carrier. For the Space Shuttle launches, a more sophisticated high-alphabet modulation technique is used. This provides for a better probability against an undesired output caused by interfering signals. The Shuttle system uses a complex command modulation format composed of various audio tones frequency modulated on the standard UHF carrier. The characters in the command word are made up of two simultaneously transmitted tones selected from seven possible frequencies. These seven tones, taken two at a time, provide an alphabet of twenty-one different characters from which a command word is formed. The transmitted sequence of characters is selectable from mission to mission. Approximately 1012 possible code combinations exist for any one mission. For the Space Shuttle launches, the range safety Command Receiver-Decoders will be used on the Solid Rocket Boosters and the External Tank portions of the complex launch vehicle. The receiver section of these units is a single superheterodyne design fixed tuned to the proper rf center frequency at the time of manufacture. The decoder section utilizes a microprocessor to effect the decoding function. The decoder is “programmed” prior to flight to recognize only the code of the mission. In addition, the microprocessor is used to accomplish the audio tone demodulation using a Fast Fourier Transform (FFT) algorithm. Solid state output switches provide the decoder output voltages to the flight termination destruct mechanism.

      Udalov, Sergei; Axiomatix (International Foundation for Telemetering, 1981-10)
      In many instances, the process of telemetering of scientific information must be accompanied by a voice conversation which either reveals the sequence of measurements or provides information as to the nature of the data gathered and/or transmitted. If such voice information can compromise the integrity of the telemetry data to an unauthorized interceptor, voice privacy equipment must be used along with the equipment used for transmission of the telemetry data. The recent developments in LSI technology provide a new capability to the design of voice encryption equipment. This is particularly true for the case where sophisticated analog encryption schemes must be employed to permit the encrypted voice information to be transmitted over the existing telephone and radio channels which are typically limited to a 3 KHz upper-frequency cutoff. This paper examines the recent developments in analog voice privacy equipment design, as indicated by the disclosures made in open literature by various manufacturers and evaluators of such equipment. Advances in the technology as well as in analytical definitions of analog voice privacy are discussed. The role of such valuable LSI chips as a microprocessor and the DES algorithm are examined. Also, in addition to considering the classic frequency/time domain permutation algorithms, developments in analog “pseudonoise” scrambling are examined in view of the data made recently available in open literature.

      Piontkowski, John S.; Stimadorakis, John; Tele-Dynamics of United Technologies; Omnitek, Incorporated (International Foundation for Telemetering, 1981-10)
      The scope of this paper deals with methods and processes undertaken to provide a significant reliability upgrade to an existing telemetry instrumentation subsystem. Selected components are produced using modern hybrid microcircuit technology in place of the previously configured discrete design approach. A comparative analysis is performed to demonstrate the resulting dramatic reliability improvement.

      Waineo, Douglas K.; Ellis, Haynes; Rockwell International Corporation (International Foundation for Telemetering, 1981-10)
      Two telemetry and communications antennas for the Shuttle Orbiter are described. Each antenna is circularly polarized and flush mounted under the thermal protection tiles. The quad antenna provides two beam positions selected by an electromechanical switch, and uses two cavity backed crossed dipole elements radiating through reduced size circular apertures called irises. The GPS/hemi antenna covers three frequencies, with 160E cone coverage at two L-band frequencies and 120E cone coverage at S-band.

      Col. Sanders, J. E.; HQ Air Force Satellite Control Facility (AFSCF) (International Foundation for Telemetering, 1981-10)
      This presentation will consist of a review of the DoD common-user Satellite Command & Control network to include: how the AFSCF evolved; a description of today’s satellite control network, its capabilities and limitations; a discussion of the approved upgrade program; and a view of what will be required for Satellite Command & Control for the 1990s.

      McElroy, D.R.; Niessen, C.W.; Massachusetts Institute of Technology (International Foundation for Telemetering, 1981-10)
      The planners of military and commercial satellite communications (SATCOM) systems for the 1980’s are considering the use of the Extremely High Frequency (EHF) band, especially those allocations from 17- to-45 GHz1. The wide bandwidths available at EHF can be used for higher capacity systems to meet projected future service requirements and for spread spectrum modulation techniques for interference rejection and/or multiple access purposes. Evolution into these higher frequencies also offers the opportunity to develop systems and signalling structures which are functionally common across multiple user communities. Such techniques provide interoperability possibilities while allowing more efficient use of space assets and minimizing the number of unique terminal developments. Due to user-platform space and prime power limitations as well as to terminal production, installation, and maintenance costs for large user populations, it is also important that EHF system configurations accommodate small, low-power terminals. One such approach involves departing from traditional SATCOM designs by incorporating increased satellite sophistication for reduced terminal size and complexity requirements. The associated spacecraft would employ advanced technologies such as uplink antenna discrimination., on-board signal processing, and downlink beamhopping. This paper presents some system configuration options for providing EHF service to mobile terminals and indicates implementation possibilities for the major spaccraft payload subsystems, with emphasis on some configuration options for the on-board signal processing unit.

      Gordon, Marc D.; Bleiweis, John; Satellite Business Systems; COMSAT General Corporation (International Foundation for Telemetering, 1981-10)
      The SBS Telemetry, Tracking and Command (TT&C) System consists of one earth station in Castle Rock, Colorado and a combined earth station and control center in Clarksburg, Maryland. The system commenced operation with the launch of the SBS-1 spacecraft in November 1980, two and one-half years after the initiation of the design study. The system design utilized as a base the experience of COMSAT and SBS personnel on the INTELSAT and COMSAT General networks. From this base, a system was designed around real-time telemetry processing for four spacecraft that included such features as: subsystem oriented spacecraft displays, centralized control over the hardware and software at both sites, human factors orientation and ease of future expansion. The major functions performed include: spacecraft commanding, ranging, orbit and attitude determination, telemetry retrieval and analysis and comprehensive monitoring and alarm system.

      Kasulka, L. H.; McDonnell Douglas Astronautics Company (International Foundation for Telemetering, 1981-10)
      The development of space platforms represents the next logical step in the exploration and utilization of space. Such platforms promise cost-effective means for performing both scientific and applications missions, such as surveys of Earth resources, for example, in low Earth orbit. Payloads mounted on these platforms can perform missions for longer periods of time than are currently available to payloads mounted in the Shuttle’s payload bay. In addition, these platforms can provide a variety of services, including a centralized power source, command and data acquisition, communications, pointing and environmental control, as well as periodic Shuttle visits for performing maintenance tasks, replenishing consumables, and replacing payloads. These platforms must be able to provide data and communications services to groups of payloads consisting of individual payloads that may or may not have common objectives and operating characteristics, and where the payload mix on a platform changes periodically during the orbital life of the platform. Appropriate data systems can be provided to support a platform development program and modest extensions of existing technology will allow these platforms to accommodate the evolution of payloads foreseen through the 1980’s.

      Qishan, Zhang; Mingrui, Zhang; Yaokun, Liu; Beijing Institute of Aeronautics & Astronautics (International Foundation for Telemetering, 1981-10)
      A sequency division multiplex (SDM) system using Walsh subcarriers was developed for the transmission of telemetry signals at our laboratory The basis of mathematics which can form a telemetry system is orthogonal function. It is the Walsh function that may form a new telemetry system. At the first stage a baseband transmission system has been designed and tested. It shows that the results of experiments are quite good, and the new system works well. At a second stage FM is used as carrier transmission. Now the whole system can work property. A proper choice of the subcarriers minimizes the crosstalk. Principles for the selection of Walsh subcarriers are deduced. It seems that the SDM system has great potentialies.

      HUANG, T. C. (International Foundation for Telemetering, 1981-10)
      Presented here is a model and analysis for evaluating bit error probability of a BPSK signal transmitted through a piece-wise linear (PWL) limited channel subject to a CW interference as well as additive Gaussian noise. The CW interference is assumed to have a random phase Θj over (0, 2π) and a fixed frequency fj which may be either inband or outof- band of the signal channel band. The analysis is carried out in two steps: First an explicit expression for the desired signal, CW tone and their harmonics conditioned on the uplink channel noise if obtained at the output of a PWL limiter. Each of these CW tones and harmonics is modeled into two components--one sinusoid with a mean power and coherently related to Θj and an equivalent Gaussian noise, independent of each other. This equivalent Gaussian noise is also independent of the noise component associated with the desired signal. The interference model is reasonable provided that the frequency fj is not close to the carrier frequency of the signal. Based on the interference model, a conditional error probability expression, whose statistics are constructed through known moment techniques, is formed and averaged over the appropriate random variables. Numerical results for interference model and error rate curves will be compared with those of hardlimited channels in order to illustrate the effect of a PWL limiter.

      Maschoff, Leon W.; Sandia National Laboratories (International Foundation for Telemetering, 1981-10)
      This report discusses application software options that are available for the design of development flight test microprocessor packages. Prelaunch parameter updates, telemetry channel calibration, system and processor self-test, raw data store, reduced data store, and telemetry formatting are some of the on-board functions that software can perform in addition to the customary control and arithmetic calculation tasks. A specific application that implements these functions as software modules and the hardware needed for support is described. The hardware in this application includes a 16-bit microprocessor that is dedicated for real time operations and an 8-bit microprocessor that services the self-test functions.

      Shaver, Robert L.; Sandia National Laboratories (International Foundation for Telemetering, 1981-10)
      High performance multi-use drones require complex control capability. Distributing the communications, control and navigation functions among different microprocessor systems connected in a network improves performance and reliability. Assembly language provides the means of optimizing time critical functions of communications and I/O control, which high level languages, such as PASCAL, ease development of mission management requirements. The use of real-time operating systems (RTOS) permits co-processing of a variety of functions in overall drone operation management. The RTOS is a software “bus” providing communications network for modules. Functions and modules are assigned priorities, enabled or suspended as needed to perform mission operational requirements via the RTOS.

      Ngan, Y.C.; Sun, C.; TRW (International Foundation for Telemetering, 1981-10)
      Two amplifier developments centered at 20 GHz based on GaAs IMPATT diodes will be discussed. The on-going developments of a 20 GHz communication amplifier sponsored by NASA Lewis using injection locking and resonant cavity combiner will be reviewed. A wideband 20 GHz amplifier to achieve 20 Watt 1 GHz bandwidth based on 3-dB hybrid couplers and stable mode of amplification, along with the results obtained from the constant voltage mode of amplification will be discussed. A wideband solid state amplifier designed as a driver for a 44 GHz terminal transmitter will be described. The amplifier is designed for 2 GHz 1-dB bandwidth centered at 44.5 GHz, with an overall gain of 40 dB. A six-stage design is used to accomplish 500 mW output power. Low cost construction and mechanical ruggedness are emphasized in this design.

      Josephson, Vernal; The Aerospace Corporation (International Foundation for Telemetering, 1981-10)
      Military Space Systems are required to have a certain level of immunity to all possible space radiation effects experiences during mission life time. These include upset and latchup from weapon x-ray bursts and cosmic rays, photo current burn-out of active junctions by large prompt doses of radiation, and performance degradation from accumulated dose due to enhanced radiation belts. Procuring piece parts capable of performing mission requirements and providing the desired immunity to these effects, and testing to verify the desired satellite immunity presents problems which must be considered when contemplating massive use of VLSIC technology where even higher desired levels of immunity may be desired. The techniques used for hardening and the testing required for hardness assurance will be discussed with emphasis on their application to VLSIC technology and its potential in space applications. An overall satellite was subjected to irradiation in order to verify its immunity to space radiation. These results will be discussed below.

      Muchow, Lee; Hoagland, J. C.; Rockwell International (International Foundation for Telemetering, 1981-10)
      During the first flight of Columbia (STS-1), the Instrumentation, Communications, and Tracking Subsystems (I-C&TSS) of the Space Shuttle orbiter used S-band links to provide (in addition to tracking) reception of digitized voice, commands, and printed or diagrammatic data at a maximum rate of 72 kilobits per second (kbps). The subsystem also provided a transmission capability for digitized voice, telemetry, television, and real-time and recorded data. Communication was via S-band directly to the ground stations; ultrahigh frequency (UHF) voice was used for communication with the landing site and some ground stations and for providing a backup link for state vector update. Audio and television subsystems served on-board needs and interfaced with the radio frequency (RF) equipment. Provisions were provided to record on-board data for post-flight playback. During aerodynamic flight following entry, the S-band link was used to supplement the UHF link that provides two-way simplex voice communication with air traffic control facilities. The I-C&T subsystem for STS-1 operated with almost textbook performance; exceptions were a dedicated signal conditioner redundancy failure, failure of the development flight instrumentation PCM recorder, and some measurement sensor failures.

      Uzdy, Z.; The Aerospace Corporation (International Foundation for Telemetering, 1981-10)
      Voice processors, including those using linear predictive coding (LPC) algorithms, are becoming more prevalent in communication systems. Several intelligibility and speaker recognition tests were used to evaluate two currently available LPC voice processors. Both text-dependent and text-independent techniques were developed. The tests are aimed at potential users, yielding quantitative data that permit performance comparisons both of systems and of human speakers and listeners.

      Webb, Roger L.; Science Applications, Inc. (International Foundation for Telemetering, 1981-10)
      Automated Calibration Systems (ACS) represent the state-of-the-art in calibration of test measurement and diagnostic of equipment (TMDE). The features and capabilities of two systems in use by the U.S. Navy are discussed in this paper. The Centrally Operated System for Metrology Information Control (COSMIC) and the Metrology Equipment Calibration and Control Analysis (MECCA) system are being developed to greatly reduce the cost of calibrating a very large inventory of test equipment at sites around the world. The benefits of an in situ calibration capability has been demonstrated at the Naval Calibration Laboratory, Tustin, California, where these calibration systems have been integrated with online databases. Future advances are anticipated through simpler human interfaces and higher throughput rates. The in situ systems now coming into use offer significant material, calibration and repair cost savings. Improved calibration support will benefit most telemetry, communication, and weapon systems.
    • A Survey of Modern Instrumentation in Aerospace TT&C Earth Terminals

      Cuccia, C. Louis; Steinberg, Philip; Ford Aerospace & Communications Corp. (International Foundation for Telemetering, 1981-10)
      This paper will provide an overview of the instrumentation of aerospace telemetry/systems in mobile and stationary earth terminals, using integrated circuits and LSI technology, microprocessors, computer graphics and measurement system. This instrumentation includes not only circuits to handle TT&C data, but also to analyze display and control system performance from the RF portion including considerations of sensitivity and effective radiated power, to tracking measurements, baseband and data system performance; to man-machine interfaces. This paper will also discuss modern display systems and techniques and will introduce the advantages of the use of the IEEE standard 488-1978 and RS-232 interface buses for the control and monitoring of TT&C equipment, including data processing with particular application to survivable earth terminals.

      Kolba, Dean P.; M.I.T. Lincoln Laboratory (International Foundation for Telemetering, 1981-10)
      Satellite communications in the allocated EHF bands, (i.e., several frequency segments from ~20 GHz to 50 GHz) has the potential for providing interference resistant communications to users employing small, mobile terminals. To realize this potential, advanced spacecraft technologies are required, such as uplink coverage through high gain directive beams, onboard signal processing, and downlink beam hopping. Simultaneous worldwide uplink coverage could be obtained via many narrow uplink antenna beams which collectively cover the earth field-of-view. When worldwide communications traffic is low volume, a reduction in space segment impact can be achieved by using a few narrow uplink antenna beams to provide the required service. To minimize delays, these beams must be able to rapidly point anywhere within the field-ofview to cover individual users who require a channel for brief communications. The agile antenna beams can be shared through demand assignment techniques. A multimode common transmission format can provide both data and control channels. The data channels are available at several rates to allow either full duty cycle data transmission or burst data transmission. With burst transmissions, a single beam can support multiple calls in a time division multiplexed fashion. The control channels are utilized in coordinating the use of satellite resources to efficiently meet the communications needs of the users. This paper discusses the use of EHF satellite communicatons to provide service to widely scattered users. The use of control channels to request and coordinate service is described. Example control protocols are presented, and system performance is indicated.